Thursday, June 16, 2016
A recent article in World Pumps magazine focused on a major oil refinery in Texas that was experiencing breakage problems with their vertical turbine pump. The plant’s engineers knew that there was a serious problem when the shaft broke twice - in exactly the same place - in less than three years.
The pump was a 4-stage, 14 GH Byron Jackson vertical turbine pump in isopentane service. A thorough inspection and analysis by the pump repair shop revealed the underlying issue was not with the shaft itself but with the use of the wrong type of bearing materials.
As noted in the article - “Alloy Bearings Cure Breakage Problems” - the bronze bearings should have been able to withstand exposure to the isopentane being pumped. However, there was an occasional inflow of caustic soda which reacted with the bronze.
The bronze bearings were replaced with GRAPHALLOY® nickel-grade bearings. Since the repair, the pump has been operating efficiently for almost three years with no reports of any problems.
Based on a recommendation from an engineer at the refinery, a GRAPHALLLOY nickel-grade material that would withstand 400°C and offer self-lubricating and corrosion resistant properties was chosen. GRAPHALLOY bushings were installed into the stuffing box, column, bowl and suction bell bearing fits.
According to the sales engineer at the pump repair shop, “GRAPHALLOY is a material that is compatible with a wide range of pumped liquids and offers a good option in high temperature applications.”
GRAPHALLOY resists attack by most corrosive liquids including sulfuric acid, hydrochloric acid, chlorine water and caustics and can withstand high temperatures without deforming or burning.
To read the full article, please click here.